Second chapter for ex-junkie

“Feel this,” says Steve Geng, grinning.

He takes your hand and rubs it on his head, the top of which, it turns out, is dented like an old fender. “That’s where the brother of a girlfriend caved my head in with a claw hammer.”

Like nearly all of Geng’s stories, this one makes him laugh. It’s a wheezy chuckle that goes “huh huh huh” and gets his shoulders bouncing. It’s a sound that says, can you believe that I actually lived this life? It’s faintly horrified and totally thrilled at the same time.

You get the horror and a sense of the thrill reading “Thick as Thieves,” Geng’s account of his nearly four decades as a small-time thief and heroin addict. Whenever he reads from the book, he interrupts himself every line or two for a hearty guffaw. His dozen-plus arrests, the East Village circle of junkie-hustlers who were his friends, the romances that ended badly, his brief sideline as a bit-part actor on “Miami Vice” -- it all just cracks him up.

He darkens only when he talks about his sister, the New Yorker staffer Veronica Geng. As he tumbled, she rose, scaling the Manhattan magazine world and becoming a renowned writer of humor pieces and a sought-after editor for authors including Philip Roth and Milan Kundera. Veronica died in 1997 at age 56 of a brain tumor, and because they were estranged at the time, Steve learned only after her death that she’d been sick.

That he never said goodbye rips him up, and as he reminisces in a booth at a restaurant in Chelsea, where he wrote much of “Thieves,” he verges now and then on tears. The book is a requiem for Ronnie, a complicated, magnetic and walled-off woman whom he adored.

Geng, 64, started writing about her and the rest of his life seven years ago after winning a raffle prize: $1,000 worth of classes at New York University. He chose a writing course and started tapping away. After meeting an editor at the publishing house of Henry Holt, Geng landed a book deal and a modest $40,000 advance.

A few Sundays ago, the New York Times gave “Thieves” a near-rave review.

“I’ve got to be honest,” says Charles McGrath, a former New Yorker editor. “When Steve got in touch with [New Yorker writer] Roger Angell and Roger enlisted me, we met with him as a courtesy. There was no reason to think he could write. But he can. He sent me his manuscript and I nearly fell over.”

Geng, cleaned up now for nine years, finds this turn of events comically improbable. And though there is a lot of tragedy in his story, he can’t do melancholy for more than a minute. He prefers to recount his misadventures as a junk-addled shoplifter, a part of his life he remembers like a hail of bullets that wounded but didn’t kill him.

He’s got to tell you this one.

It was 1971, in the Lower East Side. He was dating this woman. He hit her. They broke up. Then she called and asked him to return some stuff, and when he went to her apartment, he discovered it was a trap. Her brother cold-cocked him. Geng came to, rolled up in a carpet like a burrito. He heard two guys and his ex arguing about what to do with him.

“I heard one of them say, ‘Let’s get the car,’ and I thought, they’re going to throw me in the trunk.” He figured he was about 10 minutes from dying, depending on where they planned to dump him.

Instead, Geng wriggled out of the carpet a bit and successfully pleaded for his life.

“I said, ‘Look, I hit the poor girl, but give me a break,’ ” he recalls. He said that if they’d let him go to Beth Israel Hospital, he’d forget the whole thing.

“So they walked me a few blocks up 1st Avenue. I think they figured it was easier than dealing with a dead body.”

He pauses, staring across the restaurant. His shoulders start to bounce. “Huh huh huh.”

Geng is small and sweet-tempered and has wrinkles that form a kind of figure-eight racetrack up his cheeks and across his forehead. He has what he describes as full-blown AIDS, the result of shooting up with dirty needles, but the drug treatments work so well he expects to die of something else, and not any time soon. Still, he has that desiccated look of a man drained of vital fluid. His voice is raspy in a late-career Al Pacino kind of way.

“Being a thief was a way to avoid taking care of yourself,” he says. “I mean, if you get arrested, they lock you up and feed you and you get to hang out with wiseguys and tell war stories. It was welfare!”

After James Frey and his bestselling fraud, “A Million Little Pieces,” it’s impossible to read a recovering druggie’s memoir without asking some basic questions. Like, is this a true story?

Unlike Frey, Geng is happy to introduce you to many witnesses to events in his book -- principally, the ensemble of former criminals who were his accomplices and remain his friends.

A handful turned out for a recent book reading, and they were easy to spot, because they look ravaged. A few would give only their nicknames: Little Susie, Spanish Billy, Black Bobby.

“We were all vultures,” says Eddy Lorenzo, a burly man with gray hair who is featured in a few scenes in the book. “All these kids from the suburbs would come to the Village for sex, drugs and rock ‘n’ roll, and I’d sell them oregano or whatever and tell them it was pot.”

Everyone had a niche: fake drugs, counterfeit concert tickets, pimping for prostitutes who didn’t exist. For Geng it was stealing tons of LPs. He would walk into a record store, loosen his belt, then shove 25 or 30 albums up the back of his shirt, which would be concealed by a jacket. He’d get arrested every few months but typically was bailed out within hours.

Geng and his sister were the children of a career Army officer whom Geng describes as a rough-edged Archie Bunker type who delighted in needling his kids. “Christ, you could land a plane on those skis,” he said of Veronica’s Easter shoes one year.

In New York, Veronica dazzled bosses and dated literary stars and musicians; she was sexy, aloof and famously combative. As a writer, her specialty was the satiric and viciously witty essay.

Steve settled into a career as a hood, for reasons that still elude him. “It just played out that way, evolving gradually like a bridge hand where you run out of trump and get stuck,” he writes.

There was a brief flirtation with acting, which eventually led to a few small roles on “Miami Vice” and a scene in a film called “Miami Blues” in which he’s shot in the leg by Alec Baldwin. “I was a lousy actor. I overdid it.”

In the late 1990s, he started attending group recovery meetings, mostly to meet women. Eventually, though, drugs just started somehow to seem kind of icky -- there’s no other way to put it.

He’d been clean for a few months when he learned about Ronnie’s death. Too proud to be seen in her stricken state, she’d ceased communicating with nearly all her friends by then.

Geng is now working on a novel based on time he spent as a teen in France. He’d be thrilled to spend the rest of his life drinking coffee and typing away in diners.

“I got the life I wanted,” he says. “I wish I could have done something adventurous without breaking the hearts of people who cared about me. I wish I became a writer earlier.” He mulls that one a moment.

“But what the hell would I have written about? There’s a kind of insight you get from going to hell and back.”